The present invention relates generally to textile tubes or yarn cores, and more particularly relates to a textile tube having at least one start-up recess for capturing textile yarn during a winding operation.
The practice of winding yarn onto tubular carriers during textile production is well known in the art. During high-speed production of yarn or thread, the continuously advancing yarn is wound onto consecutive rotating cores or tubes. As a rotating tube encounters a leading strand of the yarn, the tube frictionally engages the yarn to secure an initial wind of the yarn onto the tube and simultaneously break the yarn between the tube and the preceding tube. Therefore, it is important that the tube be able to successfully engage the leading strand of yarn to secure the yarn to the tube and to break the yarn from the preceding tube.
Conventional tubes often employ a relatively deep xe2x80x9cstart-upxe2x80x9d groove for receiving the leading strand of yarn. The groove is typically xe2x80x9cVxe2x80x9d shaped and formed near one or both ends of the tube by forcing a wedged-shaped tool into the outside diameter surface of the tube. The groove has a xe2x80x9cwidexe2x80x9d section about a portion of the circumference of the tube so that the yarn can locate within the groove, and a xe2x80x9cnarrowxe2x80x9d section for catching and breaking the yarn. Such a groove is disclosed in U.S. Pat. No. 5,328,121,which is assigned to the assignee of the present invention and incorporated herein by reference in its entirety. While the start-up grooves disclosed by the ""121 patent have become an industry standard in the textile winding field, there are still improvements to be made.
In particular, it has been discovered that there are occasions where the yarn misses the wide target area of the groove and results in a failed start up, which causes production problems such as downtime and wasted material. There are several reasons why failed start ups occur, among them being (a) variation in yarn tension, (b) improper location of mechanical yarn guides, and (c) variation in groove dimensions. In addition, it has been discovered that the moisture content of the tube can have significant effects on the grooves, as most tubes are formed of paperboard and therefore are somewhat hygroscopic, i.e., capable of gaining and losing moisture. More specifically, a relatively high moisture content of the tube can cause the paperboard to swell, which effectively closes the V-shaped groove and makes successful start ups less likely. Because most textile winding operations are performed in large manufacturing facilities, controlling and maintaining the moisture content and temperature in the surrounding atmosphere is difficult. Thus, there is a need for a tube or core for winding yarn that is less reactive to humidity and other environmental conditions. There is also a need for a yarn tube that allows for easier yarn start-ups.
Some yarn tubes have attempted to improve catching the yarn by adding a relatively shallow, recessed score leading up to the relatively deep groove to help guide the yarn into the target area of the groove. While the addition of a shallow score appears to aid yarn start up compared to a groove-only configuration, adding the score creates complexity to the manufacturing process while failing to address the moisture problems that affect the V-shaped start up groove. In addition, all conventional start up grooves suffer from yarn and debris buildup and an eventual degradation of the surface of the groove. Conventional yarn tubes are thrown away when they begin failing to catch yarn, although this is quite wasteful. Thus, there is also a need to prolong the lifespan of a yarn tube in order to maximize the financial investment and maintain efficiency.
These and other needs are provided by the textile tube of the present invention, which provides a recessed score around the outer circumference of the body of the tube that provides a significant target for the yarn to engage. In addition, the recessed score has a reconditionable surface such that the yarn tube can be easily refurbished and be used for more yarn transfer cycles. The reconditionable surface may be in the form of a tape or adhesive, for example, that provides a tacky surface to entrap yarn. When the initially tacky adhesive surface becomes clogged with yarn remnants or becomes untacky for other reasons, the surface can be reconditioned by one or more means. As such, successful start-ups are more likely to occur with the tube of the present invention. In addition, the yarn tube of the present invention can be used longer than conventional yarn tubes due to the features of the recessed score and associated surface thereof. Furthermore, the recessed score of the present invention replaces the deep start-up groove of the prior art, which simplifies the manufacturing process and eliminates the moisture-caused problems of the past.
In particular, the textile tube of the present invention is used to support yarn that is wound thereon to form a yarn pack. According to one embodiment of the present invention, the tube comprises a tubular or cylindrical body extending lengthwise between opposed ends thereof and having an outer surface defining an outer diameter of the body. The body is formed from as a unitary piece from convolute or spiral winding at least one layer of paperboard material. The body defines at least one recessed score at an end thereof that has a flat bottom surface and opposing sidewalls to define a width and depth of the score. Contrary to conventional recessed scores, which are typically V-shaped and used simply to guide yarn to the start up groove, the recessed score of the present invention is preferably substantially rectangular so as to provide more surface area to capture the yarn. In this regard, the bottom surface of the score extends in a plane that is parallel to the outer surface of the body, and in a preferred embodiment the opposing sidewalls are parallel to one another and perpendicular to the bottom surface. The bottom surface is at least five times the depth and is capable of frictionally engaging or capturing yarn that comes in contact therewith. In one embodiment, the score has a width of between about 0.15-0.20 inches and a depth of 0.01-0.03 inches.
In addition, at least the bottom surface of the recessed score has an adhesive applied thereto, such as a hot melt adhesive or a double-sided tape. In this regard, the adhesive captures the yarn as the yarn is wound upon the tube. The score is formed such that the adhesive preferably does not extend past the outer surface of the tubular body, which could otherwise cause the tube to stick to an unwanted object that comes in contact therewith.
Advantageously, the recessed score of the present invention substantially retains its shape regardless of the moisture content of the tube. More specifically, the bottom surface and opposing sidewalls form a substantially rectangular cross-section that is more resistant to dimensional changes compared to rounded or V-shaped grooves. And the recessed score of the present invention provides a substantially greater surface area to capture the yarn compared to conventional grooves regardless of the moisture content of the tube. Furthermore, the recessed score eliminates the deep V-shaped grooves altogether, which simplifies manufacturing and reduces cost.
Advantageously, the adhesive is reconditionable so that the adhesive can be returned from an untacky state to a tacky state using various techniques. As such, the yarn tube of the present invention can be used repeatedly and thus reduce the frequency of replacement.